Straightening machine



@ma 5. 95I

Y G. T. CLARK.

STRAIGHTENING MACHINEA 5 Sheets-Sheet l Filed April 15.. 1921 Aug. 5, 19245 G. T. CLARK STRAIGHTENING MACHINE Filed April 13. 1921 5 Sheets-Sheet Aug. 5, 1924.; www3 G. T. CLARK STRAIGHTENING MACHINE Filed April 13. 1921 5 Sheets-Sheet 3 Aug. .5, 1924; ,504,023

G. T. CLARK STRAIGHTENING MACHINE Filed Avril 13 1921 5 Sheets-Sheet 4 G. T. CLARK STRAIGHTENING MACHINE Filed ADril 13 1921 5 Sheets-Sheet 5 Patented Aug. 5, 1924.

GEORGE T. CLARK, OF OLD ORCHARD, YMAXNE, ASSGNDR TO SACO-LOWELL SI'IGPS, 0F BOSTON, MASSCHUSETTS, A CORPORATION OF MASSACHUSETTS.

STRAIGHTENING .T JEACI-IINE.

Application filed April 13, 1921. Serial No. 460,863.V

To all i12/10my it may 00u-awa:

Beit known that l, GEORGE T. CLARK, a citizen of the United States, residing at Old Orchard, in the county of York and State of Maine, have invented certain Improvements in Straightening Machines, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to machines for straightening rods, bars, spindles, shafts. and similar articles, and it will be disclosed herein as embodied in a machine designed especially for straightening the spindles used in spinning machines. 1

Spindles of this type usually havetapered ends and in manufacturingr them it is customary to cut off a piece of steel rod of the required length and thena forge this piece of stock to approximately the desired taper, thus forming what is known as a spindle blank. Usually these blanks cool off in a lient or c-roolzed'condition and before they t an be ground to the exact taper and Size desired it is necessary to straighten them. lf these blanks are straightened while they are cold they will, nevertheless, have a. certain tendency to return to their crooked or hent condition; and while this tendency may be dormant, so to spelt, or at least insuflicient te produce any distortion of the spindle while it is at rest, still when it is run at the high speed at which thse spindles now customarily operated, this speed, together with the vibration of the machine, allows this unbalanced molecular condition to assert itself and produces an excessive vibration of the spindle. For this reason it is oreferable to perform the straightening operation while the spindles are hot enough to overcome any molecular set or biased condition wiich the spindles otherwise might have.

lt is Ythe chief object of the present invention to devisel a straightening machine forV spindles and similar articles which shall be simple .in construction, economical to manufacture, which shall be to a large degree automatic in operation, in which the dies can readily he adjusted to the contour of the article to he straightened, and which generally shall satisfy the practical requirements of a machine of this character.

preferably are made of steel and the The nature of the invention will he read ily understood from the following descriptic-n when read in connection with the ac coni'panying drawings, and the novel features will be particularly pointed out in the appendedl claims.

Referring now to the drawings,

Figure 1 is a side elevation of a machine constructed in accordance with the present invention;

Fig. 2 is a front elevation of the machine shown in Fig. l; i 4

F 3 is a cross sectional view showing the mechanism for adjusting the length of stroke ofthe dies;

F l is a vertical cross sectional view through the dies and adjacent parts;

Fig. 5 is a plan view of the parts shown in l with the upper die cut away;

Fig. 6 is a view partly in side elevation and partly incross section of a counting mechanism that 'determines the number of strokes to be given to each spindle;

Fig. 7 is a cross sectional View of a detail of the counting mechanism; and

Fig. S is a cross sectional view through the lower die andthe adjacent parts.

Briefly stated, the machine shown comprises a lower and an upper die, mechanism for reciprocating the upper die to roll the spindle. between the two dies, a counting mechanism that determines the number of reciprocations which the upper die shall male while acting on a given spindle and which controls a mechanism that raises the upper die when 'the straightening operation on the spindle has been completed. and a wnorli; gage for facilitating the positioning or the work between the dies. The detailed description of these mechanisms will he tal'en up in substantially the order in which they have just been mentioned.

Referring especially to Figs. ll, 5 and 8, it will be seen that-the lower die is made in two sections, indicated at A and B, and that each section comprises a series of bars secured by srews a lease il. The .bars hase 4. consists of a steel or iron plate of suliicient thickness to be coml Yratively rigid so that it will hold the hars in prof. tionship while still thin it to he flexed or sprung. A and B are secured to of clamps having hor.l

. .ontal arms t3 bend or spring the base 4 suiiiciently tov give the desired contour to the die surface formedby the upper edges of the series y Y of bars.

It will be seen from an inspection of Fig. 8 that the spindle S has a long taper at its right-hand end and a much shorter taper at its left-hand end. At the stage of the process of manufacture in which the straightening operationl is vperformed these end portions do not have a true tapered shape but are bulged or bowed. Consequently, the base members 4'are not straight vplates resting in an inclined plane but are each sprung or bent downwardly. It will be understood, however,that the degree to which each base plate isrsprung or bent will depend on the contour which it 'is desired to give to the upper surfaceof the. die, this contour being complemental to that ofthe part of the work whichvrests on it.

In, making dies of this character the bars 3 are secured to the base 4 by screws, or in any other convenient manner, and the upper surfaces of the bars are then ground off to form substantially a true plane. By using die sections of appropriate length and shiins of the proper height these dies can be bent or sprung to produce a great variety of tapers', curvatures or contours. It will readily be appreciated that it is a relatively expensive matter to make solid dies having surfaces of the character here required. The construction here provided, therefore, has the very' important advantage of being economical to manufacture and also of being adjustable to fit a great variety of spindles or similar articles. It therefore eects a very material saving in manufacturing costs.

The lower die is mounted in a water pan 10 of substantial construction which is secured on the upper end of a bracket 11, Figs. 1 and 2,'mounted for adjustment in vertical ways 12 and supported by a post 13, the lower end of which is threaded into a block 14 mounted on an extension from the base of the machine. A hand wheel 15 is secured Y to this post and serves as a convenient means tively heavy bars or arms 19 each having a hardened piece 20, Fig. 4, secured to its lower surface by bolts 21-21. rlhe lower surfaces of these 'bars 20 engage the work and these surfaces therefore are slightly" rounded as shown in F ig.`8. L

For the purpose of reciprocating the upper die, the entire series of bars119 ismounted on a shaft 23, Fig. 4, which is secured at its opposite ends in links 24-24 that form part Vof a parallel motion mechanism. That is, one end of the right-hand link 24'is pivoted to the upper Vend of an arm 25 mounted fast on a rock shaft 26 that is supported in bearings formed in the opposite sides of the machine frame, while the Yother' end of the link is pivoted to the lower end of an arm 2T secured fast on another rock shaft 28 that same manner. The shaft 28 projects through the left-hand side of the machine, as shown in Fig. 2, and has an arm 30 secured fast to its projecting end. This arm 1s pivoted to the upper end of a pitman rod 31, Figs. 1 l

and 2, the lower end of said rod being pivoted on a crankpin 32 projecting from a disk 33 whichfis keyed to the main shaft 34. Apulley-35 Vmounted on this shaft may be belted to any convenient source of power for the purpose of driying the machine.

lt will now be understood that when the main shaft 34 is rotating the connections just described will cause the bars 19 to reciprocate backward and forward in a horizontal plane and thus will impart a rolling motion to the spindle S, Fig. 4, positioned between the upper and lower dies. of adjusting the length of this stroke the arm 30, Figs. l, 2 and 3, is embraced by a y U-shaped block 36 between the lower legs of which the pitman rod 31 is pivoted, and thisl arm has depending lugs at opposite sides of the block 36 through which adjusting screws `37 and 38 are threaded, these screws bearing on pieces 39-39 secured to the op rock shaft 28, thus decreasing or increasing the angular movement imparted to the rock shaft by the pitman 31, and consequently adjusting the stroke of the upper die. A

For the purposeV screw 40 threaded through theupper part of the member 36 bears against the arni 30 Vand 'l serves to take up any lostlmoticn that rotherwise'might occur between the blockand the arm.

It is desirable that the work engaging faces of the bars 2O shall beparallel at all times to the correspcnding'faces of the bers of the lcwerdie, since otherwiserthe reciprocating motion would tend to squeeze the spindle outfrcm between the dies. Consequently, provision is made for the vertical l`- liv.

adjustment individually `of the bars composing the upper die. For this purpose the let'thand end, F ig. 4 of each bar 19 is bored to receive a circular projection 41 extending laterally tron one tace of a gear or toothed dislr 42, and this member is mounted eccentrically on the shaft 28, as clearly shown in Fig. 4. A tiat spring 48 is bolted to the uppersuriiace or each bar 19 and has a tooth 44which extends between the teeth ot tl e gear 42 and locks this gear against rotation. This spring also has an tip-turned portion 45 forming a thumb piece by means ot' which the free end ot the springmay be lifted to disengage the tooth 44 from the gear 42. lllhenit is desired to raise or lower one ot the bars 19 it is merely necessary to disengage the tooth 44 from the. gea-r 42 and thenrotate this gear byhand in the proper directionto raise or lower/the bar the required degree. rlhe spring is then released,A

allowing the tooth 44 to engage the gear again .and hold the gear and its eccentric 4iV in the newly adjusted position.

The upper and lower dies should be so adjusted that as thespindle S is rolled backward and forward between them'the axis of the spindle S,:Fig.r4, will travel in substantially a horizontal plane. ln Fig. 5 the bars 19 of the upper die are shown in the relative spaced relationship to the bars of the lower ydie which naturally wouldbe used, it being understood that these bars can be spaced as desired on the roclr shaft 23 by the use oi' suitable spacing collars, or in any other convenient manner. The bars 19 simply rest on the spindle, each bar taking its position independently of its neighbor. lnother words, the upper die which is composedoit these bars conforms automatically to the contour ot the spindle or other article of worlr which it engages.

The machine also includes means tor automatically raising the upper die out ot cooperative relationship to the lower die when the straightening operation on a given spindle has been completed. For this purpose the bars 19 which constitute the upper die are connected by straps 48 to a cross piece or rod 49, Figs, l and 2, which is sup ported in the forward ends of two arms TO-Ji() both secured fast to a rock shaft 51 mounted in bearingsin -the machine traine. lach ot the arms 50 has a braclret 52 secured y thereto see (i) which is connected by a nections above described to raise the upper die, the supply or' air to the cylinders being controlled by an air valve G1, Fig. 6. The movement of each plunger relatively to its cylinder is limited by a pin 62, 6, projecting through a slot 68 formed in the cylinder.

llormally the air valve is maintained in its closed position so that the cylinders 55s-55 are open to the atmosphere and the plnngers 54 are held at the lower limits of their movement by the weight ot the parts that they support. During this time the upper die rests in contact withthe lower die or on the spindle or otherI article of worl; placed between the dies. The air valve 59 is under the control of a counting mechanism which can be adjusted to predeterinine the number of strokes that will be given to each spindle. rl`his mechanism comprises a pitnian rod 65, igs. 1, 2 and 6, mounted at its lower end on a pin 66 projecting eccentriw cally from the end of the main shaft 34, the upper end oi" this rod being guided in a slot termed in a bracket 67 that is secured to the top of the machine frame. A pawl 68 secured to this pitman rod is operative normally to engage the teeth of a rack 69, best shown in Fig. 6, which is mounted to slide vertically in O'uideway formed in the machine rraine. A strap 70 connected. to the upper end oit the rack 69 runs over a pulley 71 and is connected at its opposite end to the stem 72, Fig. 7, of a piston 78 {itting loosely within a long tube or pipe 74 that contains oil or other liquid. This tube is secured tothe trame by upper and lower brackets 7 5 and 7G, respectively, 2. The back or lett-hand edge, Fig. 6, or' the rack 69 is smooth and an arm 7 7 which is secured to the valve operating lever 78 is normallyr held iirm-ly against this edge of the rack oy a strong spring 79. The pressure thus ei;- erted by the arm 77 on the racl is suhcient to hold the rack in any adjusted position in its guideway. Consequently, as the pitman rod 65 is reciprocated by the rotation of the shaft 34, the pawl 68 will raise the rack tooth by tooth and the raclr will be held against backward movement during the idle stroke of the pawl by the pressure exerted by the spring 79.

lVhile the arm 77 is resting against the rack 69 it holds the air valve lever 78 in the position shown in Fig. 6 with the valve 61 closed; but when the pawl 68 raises the lower end ot the rack clear of the arm 7 7 the spring 79 immediately swings the lever 78 about its fulcrum 80, thus causing the shortarm ot this lever to depress the valve pin 81 thereby opening the valve and admitting compressed air. from the supply pipe 82 to the cylinders 55-55. The plungers are immediately raised, thus lifting the upper die in the manner above described.

llt)

This action also produces a clock-wise rotative movement of the rock shaft 5l, as seenin Fig. 6, and this movement brings avcam 83 on the rock shaft 5l into contact with an arm Sfimounted fast on a rock shaft- 85. Another arm 86 also secured to the rock shaft S5 has a finger 87 which, at this time, engages the left-hand side, Fig. 6, of the pitman rod 65, and swings this rod toward the right far enough to move the pawl 68 out of engagement with the rack 69 and thus stop any further upward movement of the rack. The parts remain in this position with the upper die raised well above Y the lower die where it affords free access to the lower die and thus give the workman ample room to place a spindle in position between the dies.

Then it is desired to lower the upper die into cooperative relationship to the lowerdie again the workman grasps the handle 90 of the lever 78 and pulls it to- -ward the front of the machine thus mov ing the arm 7'? out from under the rack 69,

- whereupon this rack drops under the influence of gravity until it strikes a spring supported stop 91 mounted on a collar 92 which is adjustable verticallyV on the pipe or tube 74. The stop 91 preferably is made of rubber, leather, or the like, and its vertical adjustment determines the initial height of the rack and, consequently, the number of teeth that the rack must be moved'by the pawl 68 before the upper die will be raised automatically away from the work. Since this rack is raised one tooth at each reciprocation of the upper die, it is a very simple matter to predetermine the number of strokes that will be given to each spindle.

Vhen the rack 69 is dropped in the manner above described, the piston 73 retards the movement of the rack and thus reduces the shock that otherwise would be produced.

he movement of the arm 77 from under the lower end of the rack 69 closes the valve 6l, and releases the air in the cylinder 55, thus allowing the upper die to descend slowly until the bars 19 rest on the work. The rotative movement of the rock shaft 5l produced in this manner releases the arm 84 from the control of the cam S3 and thus allows the pitman rod 65, Fig. 6, to swing toward the left until the pawl 68 engages the teeth of the rack aga-in, this movement of the pitman rod being produced by a weight 937 Figs. l and 2, Vwhich is secured to the pitman. This restores the parts of the counting mechanism to their initial positions and the operations above described are then repeated. Y

The movement of the lever 'which is produced by the spring 79 is limited by a stop 941-, Fig. 6, formed on a bracket which is secured to a part of the machine frame yby set screwsior bolts and whichvialsoi- It is important in using the machine v.that 70 the spindles be placed in the proper angulari position between the dies, and for thispurpose a work gage is provided which canalso be used as an ejector. This gagecomprises' plates 96-96, Fig. 5,.secured in spaced re-A V75 lationship to bars 97-97. Fourmembers; 98 are secured'in pairs to theseplatesto enf gage and center the spindle, andthe :longitudinal position of the spindle is,deter mined by an end abutment 99.. The .gageeSO 96 rests on the upper surface of two brackets 10G-100, Figs. l and 2, secured to thewaterpan l0 at opposite sides thereof. Inorder-to hold this gage inthe proper angular relai-uy tionship `to the guides, it.is-pivotallycon-v 85" nected at each side to the4V upper end ofna, rod lOl that slides in a tube A102'whichi is secured at its lower end-to a rocksh-aft 103.1 supported in brackets 104C` secured to the4 slide or bracket Vll. Alian'dle 105,1 F ig.; 2, 90 is connectedto-the left-hand rod v102 and enables the .attendant to swing the'work gage backward and forward, -the tele'scopingconnection just described; permitting. this movement but holding.. the gagel againstfiQf swinging in a horizontal plane. StopslOGf secured to the opposite ends of each bracket l0() limit the movement of the gage.

it will'be seen that when thisgageisl moved forward tothe limit of its-strokes 10.0

it will carry thespindle'S. oflwthe lower-y die and over an inclined-apron 107,'k Figs.:1 and 4. This apron, being-below the level` of the die, will allow ther-spindle tol-drop through the gage and the spindle will then -roll down the apron into a boX 108,/ Fig. l,

which receives the straightened spindles. The operator next moves the gage-backfto about the middle lof thelower side inrea-diness to receive another spindle.V

The machine shown, as will beevident from an inspection of Fig l, is ofthe duplex type. That is, the dies, counting i mechanism and other p-artsl are lduplicated"` at the left-hand side of the machine, both4` 115 upper dies, however, being-V driven by a single mechanism. These duplicate parts have not been illustrated rsince such illustration obviously is not necessaryto aproper disclosure of the-invention. Y

In usingthe machine the Vworkman heats the spindlesl in a conveniently'located-furnace, usually keeping several spindles heat` ing at the Sametime. He places one ofl these spindles, which has been heated up 125 to about a cherry red, in the position indicated at S, Fig. 5, the upper die at this time being in its raised or inoperative posi-l tion. rlhe workman thenmovesthe lever 90 to lower the upper die, in the manner `130 above described, and the reciprocating motion or'I the upper die rolls the spindle back and forth between the dies. During this movement the spindle carries the work gage 96 to and iro with it. The bars constituting the upper dies are very heavy and, since the spindle is hot, this rolling motion eiectually straightens the spindle. The lower die is partially submerged in water, as above described, and consequently it cools the spindle rapidly en pugh to give it a fairly hard teniger while, or immediately after, it has been straightened and while it is still being rolled between the dies. rllhis rolling motion is continued until the spindle. is so cold that there is no danger of its becoming bent or -warped again, and after it has been given a number oi strokes predetermined by the counting mechanism, the upper die is raised automatically, as previously described, and the workman then grasps the handle 1.05 and moves the work gage 96 forward to effect the ejecting of the spindle. In the meantime, while this straightening operation has been going on, the workman has placed another spindle in the other side of the machine and this spindle is being subjected to the straightening action of the dies. The machine thus is automatic to a very large degree and the greater part of the workmans timeJ and attention, therefore, can be given to the heating of the spindles.

It will now be appreciated that the invention provides a machine of very simple but sturdy and substantial construction, in which the depreciation is very slow, which is convenient to operate, and in which, due to the nature of the dies, a great variety of articles can be straightened with a relatively few dies.

In using the machine it is evident that the spindle is stopped momentarily at each end of its stro-ke. lt is therefore subjected during these periods of rest to the weight of the upper die, and it would naturally be supposed that the length of the stroke should be so adjusted that the'ispindle would stop either in the same angular position at the opposite ends of its stroke, or else that its angular position at one end of the stroke should be diametrically opposite that at the other end. I ind, however, that this does not produce the best results, and that at least in thestraightening ot' spindles very much betterY results are produced by stopping the rotation 'of the spindle at some intermediate angular position at opposite ends' of the` stroke instead of at the same or diametrically *opposite angular positions. `Usually the adjustmentis made such that the spindle is stopped at one end of its stroke in an angular position about 90 different from thatn in which it is stopped at the vopposite 'tend of its. stroke. This particular angular relationship, however, is not absolutely essential, but it is preferable to so adjust the stroke that the angular position of the spindle at one end of the stroke shall besubstantially different from either the same or a diametrically opposite position from that in which it is stopped at the opposite end of the stroke. The process of straightening which involves this angular relationship of the spindle at the opposite ends oi' its stroke is not claimed herein but will be claimed in another application.

While the invention has been herein` described in connection with the hot straightening of spindles, itI will readily be appreciated that the machine can also be used successfully in the straightening of many other articles. Furthermore, it is contemplated that in some cases it will not be necessary to heat the articles to be straightened but that they can be successfully straightened in this machine at normal temperatures. It will also be understood that while I have herein shown and described the best embodiment of the invention of which I am at present awa-re, this embodiment may be modified in many particulars without departing from the spirit or scope of this invention.

Having thus described my invention what l desire to claim as new is:

l. A straightening machine comprising, in combination, a lower die having a rigid work supporting face, an upper die comprising a plurality of independent bars arranged to bear on the article to be straightcned to press it against said lower die, and means for relatively reciprocating said dies in a direction substantially parallel to said bars to rotate the article to be straightened between the dies.

2. A straightening machine comprising, in combination, a lower die having a rigid work engaging face, an upper die comprising a plurality of bars independently movable to bear on the work, whereby said upper die is conformable automatically to the contour of the work, means for relatively reciprocating said dies to roll the work between them, and mechanism for raising and lowering said upper die to move it into or out of cooperative relationship to the lower die.

3. A straightening machine comprising, in combination, upper and lower dies, means Jfor relatively reciprocating said dies to roll the article to be straightened between them, said upper die comprisingV a plurality of independent bars to bear on said article, a strap connected to each bar, and mechanism acting through said straps to raise and lower said bars.

4. A straightening machine comprising, in combination, upper and lower dies, means for relatively reciprocating said dies to roll the article to be straightened between them, said upper diel comprising a plurality of .independent bars tobear on said article,

rocating said dies to roll the work between them, and inchanism 'for raising said bars out of cooperative relationship to the vlower ldie .comprising a power operated member and-independent connections between said member and said bars.

6. A straightening `machineV comprising. in combination, upper and lower dies, said upper die comprising a plurality of independent bars, a para lel moti-on mechanism for reciprocating the upper die to cause said dies to roll the article to be straightened between thein, and .means whereby the length oit stroke of said upper die may be adjusted.

7. A straightening` machine comprising, in combination, uppei' and lower dies, means 'for relatively reciprocating said dies to roll the article to be straightened bjstweeii them, and adjustable mechanism for predetermiir ing the number of said relative'reciprocations to which each of said articles will be subjected.

8. A straighteningmachine comprising,v

in combination, upper and lower dies, mechanism for relatively reciprocating said dies to roll an article to be straightened between them, adjustable mechanism for predetermining the number of strokes to be given to said article, and mechanism operative automatically to effect a'relative movement of said dissout of cooperative relationship when said number ot strokes has been completed.

9. A straightening machine comprising, in combination, upper and lower dies, mechanism for relatively reciprocating said dies to roll van article to be straightened between them, adjustable mechanism `for predeterminingthe number of' strokes to be given to said article, and mechanismjifor automatically raising the upper die when the desired number of strokes has been coinpleted. j

1.0. A vstraightening machine"l comprising,

Yin combination, upper-and lower dies,means for relatively reciprocatingsaid Vdies toroll an article to be straightened Ibetween them,

and a gage operative-toconstantlycontrol l the positionlofsaid article betweent said'V dies during the straightening operation.

11. A straightening.machine` comprising, in combination, Vv'upper and vlower dies7 means for relatively reciprocating said dies to-'roll the article to be straightened betweenthein, awork positioninggagage mounted between said dies, and means supporting said'gage forinovementiin 'the direction of saidre- `and supporting means forV said gageenabling it to be moved to and fro between Vthe dies by' said article.

13. A straightening machine comprising in combinatiom'upper and Ilower dies, 'means for relatively reciprocating saiddistofroll the .article to'be straightened between them, and a combined workv positioning gagefand ejector mounted between saiddies.

1a. Ak straightening machinelcomprising,

yin combination, upper and lower dies, said upper die comprising a plurality o'findependent bars to bear on said article, vmeans -tor relatively reciprocating said dies in'a direction substantially parallel to said bars to rotatethe article to be straightened between the dies, `and means whereby said bars may be adjusted individually .toward or from the lower die.

15. A straightening machine: comprising,

Y in combination, upperfand-lower dies, lmeans for relatively Vreciprocating'said diesto :roll 'the article tobe straightened betweenE them, said upper die comprising a" plurality of `independent bars'to bear on said artic-le, means whereby y'sa-id; bars may be adjusted individually toward or from the lower' die,

and means whereby said lower `die 4may be djusted bodily toward or from thefupper 16. In a straightening 'machine,' a die comprising a series of bars,l a base to which Ysaid bars are rigidlyk secured, said ibase. supportingy said bars `in spaced: relationship ibut being adapted to be iiexed f-iinder :heavy pressure,and means for bending :said base and holding it ina bentcondition' tolgive the desiredfcontourto the die surface orinedby the upper edges oicfsaid bars.

17. In a straightening machinefafdie 'comprisinga series -oflbars, al base to' which said bars are rigidly :secured ,'f said-base VVsupporting said-"barsin spaced *relationship but being adaptedto be Ilexed inrderfheavy pressure, a rigid bedpandineanssfor'clamp ing'-saidbase ato saidy bed ."andffbendingfsaid *base :to -fgiveathe desired-fcontour it y he che surfaceornied .by the upper Aedges bfi-'said bars. p

18.V i In'l a straighteningvin-acliine,y ga l-die :comprising a serie'scofbarg. a'base' towhich said bars are rigidly secured, said base supporting said bars in spaced relationship but being adapted to be flexed under heavy pressure, a rigid bed on which said base is supported, shims betwen said bed and said base, and means for clamping said base to said bed and bending the base to give the desired contour to the die surface formed by the upper edges or" said bars.

19. A straightening machine comprising, in combination, upper and lower dies, means for relatively reciprocating said dies to roll an article to be straightened between them, a pawl and ratchet mechanism operated in a fixed time relationship to said means, and means controlled by said mechanism for effecting a relative movement of said dies out of cooperative relationship when they have made a predetermined number of sait relative reeiprocations.

20. A straightening machine comprising, in combination, upper and lower dies, means for relatively reciprocating said dies to roll an article to be straightened between them, a pawl and ratchet mechanism operated in a fixed time relationship to said means, an air valve controlled by said mechanism, and pneumatic means under the control of said valve for relatively moving said dies out ot cooperating relationship when they have made a predetermined number of said relative reciprocations.

2l. straightening machine comprising', in combination, upper and lower dies, means for relatively reciprocating said dies to roll an article to be straightened between them, and mechanism for automatically interrupting the operation of said dies on said article when the article has been subjected to a predetermined straighteningw action.

22. A. straightening machine comprising, in combination, upper and lower dies, means for relatively reciprocating said dies to roll an article to be straightened between them, and a gage having parts for engaging opposite sides of said article and thereby constantly controlling the position of said article during the straightening operation.

23. A straightening machine comprising, in combination, upper and lower dies, and mechanism for relatively reciprocating said dies to roll the work between them, said mechanism including means for enabling the length of the relative stroke of said dies to be adjusted.

In testimony whereof I have signed my name to this specification.

GEORGE T. CLARK. 

